Abstract: An information processing apparatus is provided which is capable of carrying out the higher memory access. The information processing apparatus includes a memory unit of a synchronous DRAM device which serves to output data synchronously with the supplied clock signal, and a control unit for controlling the access to the memory unit in accordance with an instruction issued from a CPU. The clock signal which is to be supplied to the memory unit is outputted from the control unit. The clock signal which has been outputted from the control unit is supplied to the memory unit and also is pulled back to the control unit. The control unit fetches therein the data, which has been outputted from the storage unit, at the timing which is determined on the basis of the pulled back clock signal. As a result, the control unit reduces the difference between a delay of the data which is outputted from the control unit and a delay of the clock signal which is used to determine the timing at which the data is fetched therein.

Abstract: A semiconductor memory includes a memory block consisting of a plurality of cells, a write control section, and a read control section. The write control section sets a potential to each of the plurality of cells in such a manner that the potential corresponds to a level indicated by a bit data string obtained by arranging pieces of bit data which are stored in buffers A and B and which are to be stored in the cell in the order of the buffer A and the buffer B. The read control section has a discriminator corresponding to each of the plurality of cells. The discriminator sets a threshold voltage to a potential level that corresponds to a number of discriminating operations to be performed with respect to a corresponding cell and a result of a discriminating operation already performed with respect to the cell.

Abstract: A semiconductor storage device that determines the cause of an error at the time of the error correction of data read out from a non-volatile semiconductor memory, on the basis of a previously recorded error correction count, and selects a data refresh processing or a substitute processing to perform. When the error is detected, the corrected data is rewritten back for preventing reoccurrence of error due to accidental cause. If it is determined that the reoccurrence frequency of the error is high and the error is due to degradation of the storage medium, based on the error correction count, the substitute processing is performed.

Abstract: An information processing apparatus is provided which is capable of carrying out the higher memory access. The information processing apparatus includes a memory unit of a synchronous DRAM device which serves to output data synchronously with the supplied clock signal, and a control unit for controlling the access to the memory unit in accordance with an instruction issued from a CPU. The clock signal which is to be supplied to the memory unit is outputted from the control unit. The clock signal which has been outputted from the control unit is supplied to the memory unit and also is pulled back to the control unit. The control unit fetches therein the data, which has been outputted from the storage unit, at the timing which is determined on the basis of the pulled back clock signal. As a result, the control unit reduces the difference between a delay of the data which is outputted from the control unit and a delay of the clock signal which is used to determine the timing at which the data is fetched therein.

Abstract: In the present invention, disclosed is a semiconductor memory device capable of reducing the number of erasing times of each block allocated to a cluster or the number of blocks to be erased in one writing to the minimum. As an embodiment of the present invention, when a host system 1 performs accessing, for each cluster as a unit, to the FAT partition prepared on a flash memory 17 of the semiconductor memory device 100, a CPU 6 adds an address offset value held by address offset storage section 10 to a logical address specified by the host system 1, whereby a logical address of a head sector of the cluster corresponds to a physical address of a head sector of a unit block for erasing/writing data in the flash memory 17.

Abstract: In response to a read command received by a system interface unit for accessing a plurality of blocks of data stored in said non-volatile semiconductor memory, a controller carries out selective read operations of blocks of data to two memories from the non-volatile semiconductor memory. The controller also carries out parallel operations of data transferring a first block of data, which has already been subjected to error detection and error correction operations by an error correction unit, from one of the two memories to a host system via said system interface unit and of data transferring of a second block of data to be subjected to the error detection and error correction operation, from said non-volatile semiconductor memory to the other of the two memories.

Abstract: In response to a read command received by a system interface unit for accessing a plurality of blocks of data stored in said non-volatile semiconductor memory, a controller carries out selective read operations of blocks of data to two memories from the non-volatile semiconductor memory. The controller also carries out parallel operations of data transferring a first block of data, which has already been subjected to error detection and error correction operations by an error correction unit, from one of the two memories to a host system via said system interface unit and of data transferring of a second block of data to be subjected to the error detection and error correction operation, from said non-volatile semiconductor memory to the other of the two memories.

Abstract: A semiconductor memory includes a memory block consisting of a plurality of cells, a write control section, and a read control section. The write control section sets a potential to each of the plurality of cells in such a manner that the potential corresponds to a level indicated by a bit data string obtained by arranging pieces of bit data which are stored in buffers A and B and which are to be stored in the cell in the order of the buffer A and the buffer B. The read control section has a discriminator corresponding to each of the plurality of cells. The discriminator sets a threshold voltage to a potential level that corresponds to a number of discriminating operations to be performed with respect to a corresponding cell and a result of a discriminating operation already performed with respect to the cell.

Abstract: In response to a read command received by a system interface unit for accessing a plurality of blocks of data stored in said non-volatile semiconductor memory, a controller carries out selective read operations of blocks of data to two memories from the non-volatile semiconductor memory. The controller also carries out parallel operations of data transferring a first block of data, which has already been subjected to error detection and error correction operations by an error correction unit, from one of the two memories to a host system via said system interface unit and of data transferring of a second block of data to be subjected to the error detection and error correction operation, from said non-volatile semiconductor memory to the other of the two memories.

Abstract: The memory device has an electrically rewritable nonvolatile memory used as a storage medium. To promote even deterioration throughout the memory, the erasing time and writing time are measured, the influence of scatter of cells in the memory are eliminated on the basis of the resultant measurement values and a degree of deterioration is determined with a high accuracy, whereby a memory device of a high reliability and high efficiency is realized. In order to rewrite the nonvolatile memory, therefore, the memory measures erasing time and writing time, compares erasing time with stored reference time, compares the writing time from the comparison results, and determines the degree of deterioration from the correction results. Accordingly, control is possible such that, successively, the more heavily deteriorated part of the memory is used less frequently while the less deteriorated part is used more frequently.

Abstract: A semiconductor memory device having an electrically erasable nonvolatile memory, wherein the nonvolatile memory has management information regions for individual blocks and fault registration regions for registering fault addresses. If a block is accessed and found to be faulty, the fault registration is performed so that a partially faulty memory can be used without an increase in access time. By registering the management information address for executing the interchanges of blocks in one-to-one correspondence in the administrative information region, moreover, the blocks can be interchanged depending upon the frequency of rewriting.

Abstract: High speed memory access and transparent error detection and correction using a single error correcting means are obtained. A host computer writes (2N−1)th (odd-numbered) sector data in one of the first memory and second memory (e.g., constituted by one or more memories) and 2N-th (even-numbered) sector data in the other of the first and second memory. Accordingly, (2N−1)th sector data can be read out from one of the first memory and second memory to the host computer, and at the same time (i.e., simultaneously), 2N-th sector data (i.e., next sector data to be read by the host computer) can be read out from the other of the first memory and second memory and error detection and correction can be performed in the error correcting means. Also, during a next cycle, the 2N-th (even-numbered) sector data read out from one of the first memory and second memory can be outputted to the host computer, and at the same time (i.e.

Abstract: In a memory device using an electrically rewritable nonvolatile memory as a storage medium, wherein, in order to allow the memory to deteriorate evenly, the erasing time and writing time are measured, the influence of scatter of cells in the memory being eliminated on the basis of the resultant measurement values, a substantial degree of deterioration being thereby determined with a high accuracy, whereby a memory device of a high reliability and a high efficiency is practically obtained. In order to rewrite an electrically rewritable nonvolatile memory (1), there are provided a means for measuring the erasing time and writing time, a means for comparing an erasing time with a stored reference time, a means for correcting writing time on the basis of the results of the comparison, and a means for determining deterioration on the basis of the results of the correction.

Abstract: High speed memory access and transparent error detection and correction using a single error correcting means are obtained. A host computer writes (2N−1)th (odd-numbered) sector data in one of the first memory and second memory (e.g., constituted by one or more memories) and 2N−th (even-numbered) sector data in the other of the first and second memory. Accordingly, (2N−1)th sector data can be read out from one of the first memory and second memory to the host computer, and at the same time (i.e., simultaneously), 2N−th sector data (i.e., next sector data to be read by the host computer) can be read out from the other of the first memory and second memory and error detection and correction can be performed in the error correcting means. Also, during a next cycle, the 2N−th (even-numbered) sector data read out from one of the first memory and second memory can be outputted to the host computer, and at the same time (i.e.

Abstract: An information processing apparatus is provided which is capable of carrying out the higher memory access. The information processing apparatus includes a memory unit of a synchronous DRAM device which serves to output data synchronously with the supplied clock signal, and a control unit for controlling the access to the memory unit in accordance with an instruction issued from a CPU. The clock signal which is to be supplied to the memory unit is outputted from the control unit. The clock signal which has been outputted from the control unit is supplied to the memory unit and also is pulled back to the control unit. The control unit fetches therein the data, which has been outputted from the storage unit, at the timing which is determined on the basis of the pulled back clock signal. As a result, the control unit reduces the difference between a delay of the data which is outputted from the control unit and a delay of the clock signal which is used to determine the timing at which the data is fetched therein.

Abstract: A semiconductor memory includes a memory block consisting of a plurality of cells, a write control section, and a read control section. The write control section sets a potential to each of the plurality of cells in such a manner that the potential corresponds to a level indicated by a bit data string obtained by arranging pieces of bit data which are stored in buffers A and B and which are to be stored in the cell in the order of the buffer A and the buffer B. The read control section has a discriminator corresponding to each of the plurality of cells. The discriminator sets a threshold voltage to a potential level that corresponds to a number of discriminating operations to be performed with respect to a corresponding cell and a result of a discriminating operation already performed with respect to the cell.

Abstract: A semiconductor memory device having an electrically erasable nonvolatile memory, wherein the nonvolatile memory has management information regions for individual blocks and fault registration regions for registering fault addresses. If a block is accessed and found to be faulty, the fault registration is performed so that a partially faulty memory can be used without an increase in access time. By registering the management information address for executing the interchanges of blocks in one-to-one correspondence in the administrative information region, moreover, the blocks can be interchanged depending upon the frequency of rewriting.

Abstract: In a memory device using an electrically rewritable nonvolatile memory as a storage medium, wherein, in order to allow the memory to deteriorate evenly, the erasing time and writing time are measured, the influence of scatter of cells in the memory being eliminated on the basis of the resultant measurement values, a substantial degree of deterioration being thereby determined with a high accuracy, whereby a memory device of a high reliability and a high efficiency is practically obtained. In order to rewrite an electrically rewritable nonvolatile memory (1), there are provided a means for measuring the erasing time and writing time, a means for comparing an erasing time with a stored reference time, a means for correcting writing time on the basis of the results of the comparison, and a means for determining deterioration on the basis of the results of the correction.

Abstract: An information processing apparatus is provided which is capable of carrying out the higher memory access. The information processing apparatus includes a memory unit of a synchronous DRAM device which serves to output data synchronously with the supplied clock signal, and a control unit for controlling the access to the memory unit in accordance with an instruction issued from a CPU. The clock signal which is to be supplied to the memory unit is outputted from the control unit. The clock signal which has been outputted from the control unit is supplied to the memory unit and also is pulled back to the control unit. The control unit fetches therein the data, which has been outputted from the storage unit, at the timing which is determined on the basis of the pulled back clock signal. As a result, the control unit reduces the difference between a delay of the data which is outputted from the control unit and a delay of the clock signal which is used to determine the timing at which the data is fetched therein.

Abstract: An information processing apparatus having a work suspend/resume function which allows operator to use a main memory shared by different processings even when work suspension information is saved therein. A system for allowing a same operational environment as that set up in one information processing apparatus to be easily implemented in another information processing apparatus. A main memory used by a CPU for execution of processings has a function for storing information concerning the state of the information processing apparatus prevailing at a time point when execution of a given processing is suspended by a CPU for allowing the suspended processing to be performed in continuation later on. When the suspension state information has already been stored in the main memory by a former user, the suspension state information is transferred to a removable nonvolatile storage device so that the CPU can perform other processing than the suspended one by using the main memory.